Wire lock ring insertion tool kit and method

ABSTRACT

A process is disclosed for inserting a piston pin wire lock ring, particularly Circlips and the like, into a locking groove of a wrist pin bore of a piston. The wire lock ring is radially pre-compressed and thus reduced in size in such a manner that its outside diameter is smaller than the inner diameter of the piston wrist pin bore. The wire lock ring is subsequently inserted, in its compressed state, into the pin bore where it is then uncompressed and released into the locking groove of the piston bore. A kit is disclosed for permitting the installation of a wire lock ring into a groove in a bore of a piston assembly. The disclosed invention comprises a cylindrical sleeve/tube and a plunger that slips into the sleeve/tube. The sleeve/tube has an outside diameter just slightly less than the diameter of the piston wrist pin bore containing the groove in which the lock ring is inserted. The inside diameter of the sleeve/tube is sufficiently large enough to accept the wire lock ring without over compressing, thus bending and/or compromising the wire lock ring. A plunger is also disclosed that slides through the inside diameter of the disclosed sleeve/tube, pressing the wire lock ring out of the sleeve/tube and into its awaiting groove of the bore of the piston assembly, where it will expand and lock into place.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of provisional patent applicationSer. No. 61/092,421, filed 28 Aug. 2008 by the present inventor.

FEDERALLY SPONSORED RESEARCH

Not Applicable

SEQUENCE LISTING

Not applicable

TECHNICAL FIELD

This invention relates to an assembly tool and method used in aninternal combustion engine, a compressor, or the like. Morespecifically, it is used for the installation of a wire lock ring (alsopopularly known as C Clip, Snap Ring, Piston Pin

BACKGROUND

The subject invention consists of a tool used to install a fastener on awork piece and the method of installing such a fastener. Morespecifically, this invention consists of a hand tool kit used to installa wire lock ring, thus retaining a wrist pin in a piston cross bore thatholds a piston to a connecting rod. There is further appreciation inthat such an invention has broader applications. Other desirableobjects, advantages and results of the invention will become apparentfrom the following detailed description, taken in conjunction with theaccompanying drawings, which illustrate preferred embodiments of theinvention, but are not intended to limit its application, composition orotherwise restrict it use. This invention is both a useful, simple tooland a timesaver for many applications where internal insertion into agrooved bore of a wire lock ring is required.

PRIOR ART

The assembly problem of a wrist pin retainer has been addressed for asmany years as wrist pins have had a need to be retained. Indeed, formore than 100 years wire lock rings have been used to retain wrist pins,and for those same 100 plus years the insertion of the rings hasfrustrated engineers and mechanics alike. Either to address the issue ofwrist pin retention or to address the difficulty of wire lock ringinsertion, numerous technologies have been proposed including: spirallock rings; U.S. Pat. No. 5,076,149 Everts 1991 (deforming ends of thecirclips to hold fast); wire lock rings with tabs for compressing withpliers during insertion; wire lock rings with a “dog leg” for anchoringduring insertion, etc. Despite these alternatives and other approaches,however, the fact remains the same that the wire lock ring is a standardin the industry that exists and its insertion must be addressed.

A review of the industry and of patents reveals several tools andsystems, all of which require undue pressure and/or force on the pistonassembly, are too large for use in certain restricted areas, arecumbersome and awkward to use, or require custom and complicateddesigns. U.S. Pat. No. 7,080,432 B2 Norwood 2006 shows a dual purposetool used to insert either a wire lock ring or a spiral lock ring in apiston assembly. Norwood's invention is not pertinent to the instantproposed patent because his invention requires the user to present thetool at a severe angle to the wrist pin bore of the piston as it isinserted and then rotate it around the bore to complete installation,thus prohibiting its use in constricted applications where otherpistons, cylinders, and/or engine components interfere with the angle ofattack of said tool. Moreover, given the resiliency of the spring steelof the wire lock rings, use of Norwood's invention does in fact requiresignificant pressure (contrary to the assertions of the inventor) tocompress the ring as the tool is angled into the bore of the piston.This pressure can easily cause stress to the piston, its rings, theconnecting rod, and the surrounding parts of the engine.

U.S. Pat. No. 6,789,313 B2 Hendricks 2004 contemplates a pusher and tubeassembly by which a circlip is compressed in the tube by way of aninternal, inward taper, keeping the tool and circlip perpendicular atall times. Hendricks' invention requires specific tubes for each typeand size of piston profile and pushers to match the internal diameter ofthe wrist pin into which the pusher must slide. Also, Hendricks'invention requires significant space to operate.

U.S. Pat. Application Publication No. US 2008/0295331 A1 Stemer 2008shows a multi-part tool by which the user inserts a circlip into aninternal tapered “pin bore” by way of a “tightening pin,” and then matedto a “stop pin” that is run through the center diameter of the wristpin—all parts necessarily aligned parallel to the longitudinal axis atall times. Stemer's invention requires specific tubes for each type ofpiston profile and size and pins to match the internal diameter of thewrist pin into which the pusher must slide, as well as significant roomto work the tool from both sides of the piston—not always possible insome applications.

U.S. Pat. No. 6,507, 985 B1 Loughlin 2003 shows a sleeve member with aninternal tapered passage and plunger assembly by which the sleeve isaligned with the wall of the piston, the circlip inserted into thesleeve, the plunger assembly inserted into the sleeve, and then into theinternal diameter of the wrist pin. Loughlin's invention requiresspecific sleeves for each type of piston profile and pushers to matchthe internal diameter of the wrist pin into which the pusher must slide,as well as significant manipulation room in order to engage allcomponent parts of the tool and keep them perpendicular during use.

The subject invention addresses the shortcomings of the foregoing artand thus provides the following benefits:

decreases engine assembly time for inserting circlips;

avoids marring of pistons with general-purpose tools now commonly usedfor inserting (i.e., screwdrivers);

decreases worker/technician fatigue;

avoids possible injury from use of general purpose tools when the toolslips and gouges the worker/technician;

allows for one size tool to fit all applications within that range(i.e., a 22 mm tool will work on all pistons with 22 mm wrist pins: thesame tool can be used on a variety of piston profiles regardless ofwrist pin offset, ring (e.g., oil scavenge ring) configuration, andinternal diameter of wrist pin;

requires minimal space to maneuver tool: the tool can accomplish itspurpose in very tight spaces, avoiding interference with other pistons,cylinders, and engine component parts;

does not require component tool parts or circlip to be kept at rightangles, parallel, or aligned along any axis;

requires very small angle of attack, thus allowing for full tool use invery restricted areas;

allows insertion of wire lock ring in the tube/sleeve of the tool priorto insertion into the piston, thus the stress of compressing the circliphas already been accomplished away from the engine, eliminating anystress, twisting, or leverage on the piston (or its very fragile pistonrings) while it is on the engine.

BRIEF DESCRIPTION OF THE INVENTION

The insertion of a wire lock ring into a grooved bore, to establish awrist pin abutment, is a frustrating and difficult task. Wire lock ringsare made of hardened spring steel with very little tolerance forcompression. The outside diameter of wire lock rings must be compressed,however, to clear through the bore in the piston to reach its ultimateresting place. Many mechanics attempt to “manually” compress the wirelock ring into the piston wrist pin bore by leveraging one end of theopen ring into the groove of the bore and attempting to compress thering with a flat-blade screwdriver. Occasionally this manual, in-placecompression method may work, but often it ends in the flat blade of thescrewdriver slipping off the round edge of the wire lock ring andgouging the piston with the screw driver, gouging the mechanic's fingerwith the screwdriver, and/or sending the compressed wire lock ring likea projectile across the mechanic's shop to be lost forever. The presentinvention provides a remedy for the woes of the mechanic in installingthe wire lock rings. The present invention allows the mechanic tocompress the wire lock ring before installing it into the bore of thepiston. By compressing the wire lock ring in a controlled fashion, priorto installing it into the bore, without having to contort to access aremote piston wrist pin bore, the mechanic can spare the enginecomponent parts undue stress and abuse, spare his or her physical wellbeing, and save time looking for lost wire lock rings that have flownacross the shop, or worse, into the engine itself. The simple design ofthe present invention, without any intricate or complicated mechanism,allows the mechanic to quickly install the wire lock rings smoothly andsafely.

DRAWINGS

FIG. 1 shows an engineer's drawing of the side view of the plunger andthe sleeve/tube.

FIG. 2 shows the assembled invention with the plunger inserted into thesleeve/tube.

FIG. 3 shows a wire lock ring as it is prepared to be inserted into thesleeve/tube.

FIG. 4 shows a wire lock ring as it is inserted into the sleeve/tubewith the aid of a flat-blade screwdriver.

FIG. 5 shows a wire lock ring inserted into the sleeve/tube.

FIG. 6 shows the assembled invention with the wire lock ring inserted inthe tool, the plunger in the sleeve/tube, and with the invention held inthe hand of the user.

FIG. 7 shows a piston assembly with a piston wrist pin bore as theinvention with the compressed wire lock ring in place is presented tothe wrist pin bore of the piston.

FIG. 8 shows the invention as it is inserted into the bore of the pistonassembly as the plunger is being pressed into the sleeve/tube andsleeve/tube pulled back.

DRAWINGS—REFERENCE NUMERALS

1 Sleeve/Tube 2 Sleeve/Tube Outside Diameter (small end) 3 Sleeve/TubeInside 4 Sleeve/Tube Outside Diameter Diameter (large end) 5 Sleeve/Tubelength 6 Plunger Diameter (small end) 7 Plunger Length 8 Plunger HeadDiameter (large end) 9 Blind Tapped Hole 10 Plunger 15 Wire Lock Ring(Circlip) 17 Opening of Wire Lock Ring 20 Screwdriver 37 Wrist Pin Boreof Piston Assembly 38 Piston Assembly

DETAILED DESCRIPTION

FIG. 1 shows the sleeve/tube and plunger. 1 represents the sleeve/tube.2 represents the outside diameter (“OD”) of the sleeve/tube. Eachapplication will require a specific diameter sleeve/tube to correspondto the diameter of the wrist pin bore in the piston assembly. Thesleeve/tube OD is approximately 0.010″ smaller than the bore (37) thusallowing free and easy insertion of the sleeve/tube into the bore.

The inside diameter (“ID”) of the sleeve/tube 3 should be large enoughto accept the compressed wire lock ring 15 without over compressing itand thus distorting or otherwise stressing it. 3 must be large enough tonot over stress the wire lock ring 15, yet not so large as to sacrificethe wall thickness of the sleeve/tube 1. If the sleeve/tube wallthickness is too thin, the wall of the sleeve/tube will be deformed bythe hard edge of the wire lock ring as it is pressed into thetube/sleeve.

4 shows the larger OD portion of the sleeve/tube that provides the toolwith more rigidity and provides space for knurling to provide bettergrip for installation of the tool into the bore and during installationof the wire lock ring into the sleeve/bore. 5 represents the length ofthe sleeve/tube's small diameter, the length of which must be longenough to insert past the outside of the piston and into the bore of thepiston assembly to the ring groove itself.

10 represents the plunger itself. 6 shows the outside diameter (“OD”) ofthe plunger that is approximately 0.010″ smaller than the insidediameter of the sleeve/tube 3. Since the OD of the plunger is slightlysmaller than the ID of sleeve/tube, the plunger slides smoothly withoutinterference through the sleeve/tube.

7 shows the length of the plunger as longer than the length of thesleeve/tube (length of 4 plus length of 5). With the plunger lengthlonger than the sleeve/tube length, the plunger will be able to push thewire lock ring past the end of the sleeve/tube and into the groove ofthe bore of the piston assembly 37.

8 shows the head of the plunger which will allow the user to have asurface upon which to push the plunger into the sleeve/tube 1. The headof the plunger 8 will also ensure a positive stop to prevent the plungerfrom being pushed too far into the sleeve/tube 1 or into the pistonwrist pin bore 37. The diameter of the head 8 is larger than the ID ofthe sleeve/tube 1.

9 shows a blind tapped hole for attachment of an extension to theplunger to allow for more leverage or additional manipulation.

FIG. 2 shows the insertion of plunger 10 into sleeve/tube 1 through thelarge OD end of the sleeve/tube 1.

FIG. 3 shows a wire lock ring 15 as it is being prepared for insertioninto the sleeve/tube 1. The closed end of the wire lock ring is insertedfirst into the sleeve tube, while the open end of the wire lock ring 17is opposite of the opening.

FIG. 4 shows the use of a flat blade screwdriver 20 to compress the wirelock ring 15 to fit into the sleeve/tube 1.

FIG. 5 shows the wire lock ring 15 compressed into the sleeve tube 1,with the open portion of the wire lock ring 17 protruding above the edgeof the sleeve/tube.

FIG. 6 shows the assembled tool with the plunger 10 inserted into thesleeve/tube 1. The wire lock ring 15 is compressed in the sleeve/tube 1and the plunger 10 is pressed against the ring. The wire lock ring 15continues to protrude from the sleeve/tube 1 and is recessed onlyslightly below the opening of the sleeve/tube 1. The wire lock ring isat an acute angle in the sleeve/tube 1, not parallel to the axis of thetool or at a right angle to the face of the plunger 10. The compressedwire lock ring 15 is now toward the opening/edge of the sleeve/tube 1.

FIG. 7 shows a piston assembly 38 with a piston wrist pin bore 37 as thesleeve/tube 1 with the compressed wire lock ring 15 is presented to thebore 37. As in FIG. 6, the wire lock ring 15 continues to protrude fromthe sleeve/tube 1 and is recessed only slightly below the opening of thesleeve/tube 1. The wire lock ring 15 continues to be at an acute anglein the sleeve/tube 1, not parallel to the axis of the tool or at a rightangle to the face of the plunger 10. The base (closed portion) of thewire lock ring 15 touches the wall of the tube/sleeve 1 where it alsocontacts the edge of the face of the plunger 10.

FIG. 8 shows the invention as it is inserted into the bore of the pistonassembly 37 and as the plunger 19 is being pressed into the sleeve/tube1 and the sleeve/tube pulled back.

Operation

The sleeve/tube is placed on a hard surface with the narrow diameterpointing up (FIG. 3). The closed end of a wire lock ring is then placedacross the opening of the sleeve/tube (FIG. 3). Using a flat bladescrewdriver, the wire lock ring is pressed into the sleeve/tube (FIG.4). Only about ½ of the wire lock ring need be compressed into thesleeve/tube, leaving about ½ or more of the wire lock ring proud of thesleeve/tube (FIG. 5).

The plunger is inserted into the large outside diameter end of thesleeve/tube and while the open end of the wire lock ring is stillprotruding from the sleeve/tube, the plunger is pressed against theclosed end of the clip (FIG. 6), being sure not to push the wire lockring out of the sleeve/tube. The plunger is pushed further into thesleeve/tube and the wire lock ring adjusted (tilted) so that it is nolonger standing straight up and down (at a right angle to the axis ofthe tool) as in FIG. 5, but is at an acute angle inside the sleeve. Thewire lock ring needs to be slanted inside the sleeve/tube, with the openend of the ring still protruding from the end of the sleeve/tube. Thebase (closed portion) of the wire lock ring touches the wall of thetube/sleeve where it also contacts the edge of the face of the plunger.With the wire lock ring protruding from the sleeve/tube, the inventionis inserted into the wrist pin bore of the piston (FIG. 7). Whileholding the invention in place in the bore, the plunger is pressed andthe sleeve/tube smoothly pulled back until the wire lock rings slidesout of the sleeve/tube and expands fully into place in the groove in thepiston wrist pin cross bore (FIG. 8).

Conclusions, Ramifications, and Scope

Accordingly, based upon the foregoing, the reader will see that theinstant invention clearly is more useful than any of the prior art inthat it allows for one size tool to be used on numerous applicationsregardless of style or profile of piston. The instant invention is moreelegant in its simplicity than the prior art in that it has fewer partsand is more versatile in its application. Moreover, the instantinvention provides a novel and original method and device to quickly,conveniently, and safely insert wire lock rings, with no known tooloffering similar or competing features. This new and useful inventionallows the user flexibility in its use by allowing the user to insertthe wire lock ring by way of the invention at angles not strictlydetermined or dictated by the tool. The invention can be used, unlikethe prior art, in assembly situations requiring close quarter operation,thus providing access to an otherwise restricted piston and its crossbore. The invention reduces fatigue of the technician and reducesassembly time by simplifying the challenging task of wire lock ringinsertion, and ensures that no stress is placed on any of theassemblies. With eliminated damage to component parts, eliminated threatof personal injury, and reduced assembly times, the instant inventionclearly provides new, useful, and novel advantages over the prior andexisting art.

Although the description above contains many specifications, theseshould not be construed as limiting the scope of the embodiments, but asmerely providing illustrations of some of the presently preferredembodiments. For example, the invention can be manufactured to otherproportions to allow for applications requiring special needs, or can beused in any application, other than engine or piston assembly, requiringinsertion of wire lock rings. Also, the instant invention can be usedfor insertion of any style internal diameter retaining devices, otherthan the wire lock ring style, such as Rotor Clip Retaining Rings.

Thus the scope of the embodiments should be determined by the appendedclaims and their legal equivalents, rather than just specifically by theexamples given.

1. A method of inserting a piston pin locking ring into a locking grooveof a pin bore of a piston, the method which comprises: a. Placing thetube/sleeve on a hard surface with narrow diameter pointing up (FIG. 3).Placing closed end of a piston pin locking ring across the opening of asleeve/tube and using a flat screwdriver (preferably one with anotch/groove ground into the tip to accept the clip), or merely pressingdown, and pressing the piston pin locking ring about ½ the distance ofthe ring into the sleeve/tube (FIGS. 4 and 5). Leaving about ½ or moreof the circlip proud of the sleeve/tube (FIG. 5). b. Sliding the plungerinto the sleeve/tube (from the larger diameter end), and while the openend of the piston pin locking ring is protruding from the sleeve/tube,sliding said plunger against the closed end of the piston pin lockingring, being sure not to push the circlip out of the sleeve/tube (FIG.6). Pushing the plunger further into the sleeve/tube, adjusting(tilting) the piston pin locking ring so that it is no longer standingstraight up and down as in FIG. 5, but is at an acute angle inside thesleeve/tube. The closed end of the piston pin locking ring, being justbelow the lip of the sleeve/tube, touches the wall of the sleeve/tubeand the edge of the face of the plunger. Ensuring that the piston pinlocking ring is slanted at an angle inside the tube/sleeve, and that theopen end of the circlip protrudes slightly past the opening of thesleeve/tube. c. Grasping the sleeve/tube between fingers and pressingwith thumb against the plunger, with the circlip protruding from thesleeve/tube, inserting circlip into the wrist pin hole of the piston(FIG. 7). Pushing the entire tool firmly against the wrist pin or untilthe circlip is in its position adjacent to its groove in the piston,pushing firmly with thumb against the plunger, pulling back on thetube/sleeve until the circlip is ejected from the tube/sleeve andexpands fully into its groove in the piston adjacent to the wrist pin(FIG. 8).
 2. A tool kit for installation of a wire lock ring into a boregroove of a wrist pin cross bore of a piston assembly, the toolcomprising: a. a cylindrical sleeve/tube with one end with an outsidediameter corresponding to the piston wrist pin bore (less approximately0.010″) and an inside diameter to accommodate a compressed wire lockring; i. the length of said tube/sleeve to be long enough to enableinsertion of the sleeve/tube carrying the compressed wire lock ring intothe groove in the bore; ii. with the opposite end of the sleeve/tubecomprising a large diameter end to allow the tool to be manually graspedby the user during insertion of the wire lock ring into it and duringinsertion of the tool kit into the bore, with the outside diameter ofthe large end of the sleeve/tube to be larger than the opposite end ofthe sleeve/tube to provide rigidity for the tool and additional surfacearea for grip; iii. with the inside diameter of the large end of thesleeve/tube to be a constant diameter and contiguous to the opposite endof the sleeve/tube; b. a plunger with a diameter that is approximately0.010″ smaller than the inside diameter of the sleeve/bore, thusallowing the plunger to slide smoothly without interference through thesleeve/tube; i. with the length of the plunger being longer than thesleeve/tube to enable the plunger to push the wire lock ring past theend of the sleeve/tube and into the groove of the bore of the pistonassembly; ii. with the plunger having a head that will allow the user tohave a surface upon which to push the plunger into the sleeve/tube wheresuch head also ensure a positive stop to prevent the plunger from beingpushed too far into the sleeve/tube or into the piston wrist pin boreand where the diameter of the head is larger than the inside diameter ofthe sleeve/tube; iii. with the head of the plunger having a blind tappedhole for attachment of an extension to the plunger to allow for moreleverage or easier manipulation depending upon the specific application.